全文获取类型
收费全文 | 4648篇 |
免费 | 571篇 |
国内免费 | 427篇 |
专业分类
电工技术 | 318篇 |
综合类 | 297篇 |
化学工业 | 493篇 |
金属工艺 | 278篇 |
机械仪表 | 394篇 |
建筑科学 | 819篇 |
矿业工程 | 44篇 |
能源动力 | 260篇 |
轻工业 | 25篇 |
水利工程 | 70篇 |
石油天然气 | 39篇 |
武器工业 | 11篇 |
无线电 | 410篇 |
一般工业技术 | 971篇 |
冶金工业 | 77篇 |
原子能技术 | 35篇 |
自动化技术 | 1105篇 |
出版年
2024年 | 17篇 |
2023年 | 187篇 |
2022年 | 242篇 |
2021年 | 174篇 |
2020年 | 303篇 |
2019年 | 225篇 |
2018年 | 212篇 |
2017年 | 268篇 |
2016年 | 323篇 |
2015年 | 254篇 |
2014年 | 376篇 |
2013年 | 388篇 |
2012年 | 455篇 |
2011年 | 367篇 |
2010年 | 277篇 |
2009年 | 330篇 |
2008年 | 138篇 |
2007年 | 248篇 |
2006年 | 247篇 |
2005年 | 105篇 |
2004年 | 52篇 |
2003年 | 44篇 |
2002年 | 42篇 |
2001年 | 46篇 |
2000年 | 34篇 |
1999年 | 45篇 |
1998年 | 18篇 |
1997年 | 9篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 15篇 |
1993年 | 9篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 18篇 |
1987年 | 41篇 |
1986年 | 56篇 |
1985年 | 9篇 |
1980年 | 1篇 |
1979年 | 5篇 |
排序方式: 共有5646条查询结果,搜索用时 31 毫秒
91.
Mean shift(均值漂移)算法核函数窗口的带宽目前仍没有一个统一的确定标准.对整体图像根据Canny算子提取的边缘方向信息分成3类子图,一类是规则边缘子图,由规则边缘像素组成;第2类为非规则边缘子图,由边界方向变化剧烈的边缘像素组成;第3类是非边缘子图,由区域内部平坦区域和噪声区域组成.规则边缘子图和非边缘子图采用大窗口使区域内部更为平滑,并使噪声区域达到更高的抗噪性能,非规则边缘子图用小窗口可保持更高的边界精度.实验采用金属断口图像进行分割,结果表明,针对不同子图采用不同核函数带宽的方法使分割后的金属断口图像边界更准确,抗噪性能也更强. 相似文献
92.
Carlos Ariño Emilio Pérez Antonio Sala 《Engineering Applications of Artificial Intelligence》2010,23(8):1420-1427
This paper presents a novel control design technique in order to obtain a guaranteed cost fuzzy controller subject to constraints on the input channel. This guaranteed cost control law is obtained via multi-parametric quadratic programming. The result is a piecewise fuzzy control law where the state partition is defined by fuzzy inequalities. The parameters of the Lyapunov function can be obtained previously using Linear Matrix Inequalities optimization. 相似文献
93.
94.
Ling-Yuan Hsu Shi-Jinn Horng Pingzhi Fan Muhammad Khurram Khan Yuh-Rau Wang Ray-Shine Run Jui-Lin Lai Rong-Jian Chen 《Expert systems with applications》2011,38(5):5525-5531
In this paper, we proposed a modified turbulent particle swarm optimization (named MTPSO) model for solving planar graph coloring problem based on particle swarm optimization. The proposed model is consisting of the walking one strategy, assessment strategy and turbulent strategy. The proposed MTPSO model can solve the planar graph coloring problem using four-colors more efficiently and accurately. Compared to the results shown in Cui et al. (2008), not only the experimental results of the proposed model can get smaller average iterations but can get higher correction coloring rate when the number of nodes is greater than 30. 相似文献
95.
Partner selection is a major issue in the formation of a virtual enterprise. In practice, in the partner selection process, the information about the candidates and their performances are incomplete and uncertain. Vague sets theory is one of the methods used to deal with uncertain information. In this paper, a new method based on vague sets is proposed to deal with the partner selection problem in the formation of a virtual enterprise while the factors of satisfaction degree, due date, cost and the precedence of tasks are taken into account. On the basis of the agreement index of satisfaction degree, the formulated partner selection problems are interpreted so as to maximize the minimum agreement index. To solve the problem, an improved particle swarm optimization (PSO) algorithm is proposed. Finally, the simulation of a numerical example demonstrates that the method is effective. 相似文献
96.
Gui-Wu Wei 《Expert systems with applications》2011,38(4):2984-2989
To study the problem of multiple attribute decision making in which the decision making information values are triangular fuzzy number, a new group decision making method is proposed. Then the calculation steps to solve it are given. As the key step, a new operator called fuzzy induced ordered weighted harmonic mean (FIOWHM) operator is proposed and a method based on the fuzzy weighted harmonic mean (FWHM) operator and FIOWHM operators for fuzzy MAGDM is presented. The priority based on possibility degree for the fuzzy multiple attribute decision making problem is proposed. At last, a numerical example is provided to illustrate the proposed method. The result shows the approach is simple, effective and easy to calculate. 相似文献
97.
98.
Dimension reduction methods are often applied in machine learning and data mining problems. Linear subspace methods are the commonly used ones, such as principal component analysis (PCA), Fisher's linear discriminant analysis (FDA), common spatial pattern (CSP), et al. In this paper, we describe a novel feature extraction method for binary classification problems. Instead of finding linear subspaces, our method finds lower-dimensional affine subspaces satisfying a generalization of the Fukunaga–Koontz transformation (FKT). The proposed method has a closed-form solution and thus can be solved very efficiently. Under normality assumption, our method can be seen as finding an optimal truncated spectrum of the Kullback–Leibler divergence. Also we show that FDA and CSP are special cases of our proposed method under normality assumption. Experiments on simulated data show that our method performs better than PCA and FDA on data that is distributed on two cylinders, even one within the other. We also show that, on several real data sets, our method provides statistically significant improvement on test set accuracy over FDA, CSP and FKT. Therefore the proposed method can be used as another preliminary data-exploring tool to help solve machine learning and data mining problems. 相似文献
99.
Xueqing Zhang 《Expert systems with applications》2009,36(4):7519-7527
Best value is the ultimate goal in the development of infrastructure projects through public private partnerships. This necessitates a best value approach in selecting the right private partner (i.e., the concessionaire) that involves evaluating alternative concessionaires against multiple conflicting criteria of varying degrees of importance and uncertainty. Correspondingly, this paper has developed a quantitative best value concessionaire selection system. The essence of this system lies in (1) the establishment of four-package evaluation criteria that can effectively measure the concessionaire’s capability and “predict” its future performance toward achieving the government’s best value objectives and (2) the development of a fuzzy-composite scoring and ranking method that ensures the right “tradeoff” between these criteria by relatively weighting fuzzy scores and logically aggregating evaluation results. This system would not only provide the government integrated assessments of alternative concessionaires so as to award the contract to the right concessionaire whose proposal is perceived to be able to maximize the outcome of the project, but also satisfy the requirements of the legal decision in order to withstand legal challenges concerning the public contract awarded in a best value approach. A hypothetical case study is provided to demonstrate the application of this best value concessionaire selection system. 相似文献
100.